# Arrays and Strings

One type of problem asks that you to reduce the array or string into a smaller set or a single value. Another type of problem asks that you compare two strings or arrays. Remember that an array or string is represented mathematically as a set, and most problems are asking you to reduce that set into a smaller set (or a single value.)

When evaluating time complexity, keep in mind the time complexity of the following operations:

• sorting an array - $$O(n \ log \ n)$$
• iterating through an array - $$O(n)$$

### Topics

#### CCI - Chapter 1

Problems are taken from Cracking the Coding Interview.